profitability_index

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Calculate' implies a read-only computation, but the description doesn't specify whether this tool modifies data, requires permissions, has rate limits, or what the output format is. For a tool with no annotation coverage, this leaves significant behavioral gaps unexplained.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise with no wasted words—just three words. It's front-loaded and to the point, though this brevity contributes to gaps in other dimensions. Every sentence (in this case, the single phrase) earns its place by stating the core action.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (financial calculation with 3 parameters), lack of annotations, and no output schema, the description is incomplete. It doesn't explain what profitability index is, how it's used, what the output means, or any edge cases. For a tool in a server with many financial analytics siblings, more context is needed to guide proper use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 33% (only the 'rate' parameter has a description), so the description must compensate but doesn't. It adds no information about parameters beyond what's in the schema. The baseline is 3 because the schema covers the parameters structurally, but with low description coverage, the description fails to enhance understanding of what 'initialInvestment' or 'cashFlows' represent in this context.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Calculate profitability index (PI)' states the action and resource but is vague about what PI represents or how it differs from similar financial metrics. It doesn't distinguish this tool from sibling tools like calculate_npv or calculate_irr, which are related investment analysis tools. The purpose is clear at a basic level but lacks specificity and differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. With many sibling tools for financial analysis (e.g., calculate_npv, calculate_irr, payback_period), there's no indication of when profitability index is preferred, what problems it solves, or any prerequisites. Usage is implied only by the tool name, not explained.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.